This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 11-197551, filed Jul. 12, 1999; and No. 11-197552, filed Jul. 12, 1999, the entire contents of which are incorporated herein by reference.
The present invention relates to a blurring correction apparatus for correcting an adverse influence from xe2x80x9cblurringxe2x80x9d produced at an image taking apparatus and to an image taking apparatus having such a blurring correction apparatus.
Conventionally, an apparatus for preventing a lowering in quality of an image resulting from xe2x80x9chand blurringxe2x80x9d produced at a time of taking an image or picture has been variously proposed.
As one example, JPN PAT APPLN KOKAI PUBLICATION No. 6-148730 discloses a camera""s hand blurring correction apparatus for effecting xe2x80x9cblurringxe2x80x9d correction by varying a refractive index of a prism comprised of an optical anistropic medium and, by doing so, deflecting that light beam.
In the blurring correction apparatus disclosed in the above-mentioned Publication, use is made of, as a correction optical member, a prism (electric deflection member) formed of an optical anisotropic medium and, since it is possible to decrease the number of mechanical movable parts for blurring correction, this can contribute to reducing a size of an apparatus obtained.
In the blurring correction apparatus disclosed in the above-mentioned Publication, no consideration is paid to a detecting device for detecting a state of an electric deflection member. That is, the refractive index varies by voltage control and, since this state variation is not a mechanical one, it is not possible to detect it. The user cannot know whether or not a desired blurring correction operation is ensured and feels somewhat uneasy about the blurring correction operation.
Further, in order to obtain the refractive index corresponding to a blurring amount, a table for supply voltage against the blurring amount is utilized. It is preferable that this table be properly updated so as to be made properly responsive to the xe2x80x9cagingxe2x80x9d and temperature variation. Since, however, it is not possible to detect the above-mentioned refractive index state, the updating of the table cannot be done.
For the blurring correction apparatus disclosed in the above-mentioned Publication it is difficult to maintain the blurring correction performance stable.
The prism formed of the above-mentioned optical anisotropic medium ensures no adequate responsiveness when the refractive index is varied and it may be considered that, in some cases, an irregular action such as the xe2x80x9chand blurringxe2x80x9d cannot be properly handled. In particular, in the case of a lower temperature involved and in the event of the xe2x80x9cagingxe2x80x9d, it may be predicted that their responsiveness is further lowered, thus presenting a somewhat greater problem.
The present invention has been achieved with the above in view and the object of the present invention is to provide a blurring correction apparatus for performing blurring correction by varying the refractive index of a member, under the control of a supply voltage, comprised of an optical anisotropic medium which can maintain a blurring correction performance stable by a simpler method.
The present invention also provides an image taking apparatus having a blurring correction apparatus which can maintain a blurring correction performance stable by a simpler method.
According to a first aspect of the present invention, there is provided a blurring correction apparatus mounted on an image taking apparatus, comprising:
blurring detecting means for detecting a blurring state of the image taking apparatus;
refractive index variable electric deflection means arranged in an image taking optical system of the image taking apparatus and used for correcting an adverse effect resulting from the blurring of the image taking apparatus;
controlling means for controlling the electric deflection means in accordance with an output of the blurring detecting means; and
refractive index state detecting means for detecting a refractive index state of the electric deflection means, wherein
the controlling means performs operation control of the electric deflection means on the basis of a result of detection by the refractive index state detecting means.
According to a second aspect of the present invention, there is provided a blurring correction apparatus mounted on an image taking apparatus, comprising:
blurring detecting means for detecting a blurring state of the image taking apparatus;
refractive index variable electric deflection means arranged in an image taking optical system of the image taking apparatus and used for correcting an adverse effect resulting from the blurring of the image taking apparatus;
voltage generating means for generating a voltage for setting a refractive index of the electric deflection means;
refractive index state detecting means for detecting a refractive index state of the electric deflection means; and
voltage controlling means for controlling a voltage generated at the voltage generating means on the basis of outputs of blurring detecting means and refractive index state detecting means.
According to a third aspect of the present invention, there is provided a blurring correction apparatus mounted on an image taking apparatus, comprising:
first and second electric deflection means arranged in an image taking optical system of the image taking apparatus to allow image taking light to be deflected in first and second directions in accordance with a supply voltage, the deflection directions of the first and second electric deflection means being arranged orthogonal to an image taking optical axis on an image-taking image formation surface;
first and second blurring detection means for detecting blurring in first and second directions of the image taking apparatus;
blurring calculating means for calculating first and second blurring amounts in the first and second directions from outputs of the first and second blurring detecting means;
determining means for determining deflection directions of the first and second electric deflection means on the basis of first and second blurring amounts calculated by the blurring calculating means;
voltage setting means for finding first and second voltage values supplied to the first and second electric deflection means in accordance with the deflection directions of the first and second electric deflection means determined by the determining means;
voltage generating means for supplying first and second voltages to the first and second electric deflection means in accordance with the first and second voltages found by the voltage setting means; and
control means for controlling the above-mentioned respective means to perform a blurring correction operation, here, the blurring correction operation being terminated before an image taking operation by the image taking apparatus.
According to a fourth aspect of the present invention, there is provided a blurring correction apparatus mounted on an image taking apparatus, comprising:
first and second electric deflection members arranged in an image taking optical system of the image taking apparatus to allow refractive index to vary in accordance with a supply voltage, here, the first and second electric deflection members being such that deflection directions are arranged orthogonal to an image taking optical axis on a shot image formation surface;
first and second blurring detecting sensors for detecting blurring in first and second directions of the image taking apparatus;
first and second blurring calculating sections for calculating first and second blurring amounts in the first and second directions from the outputs of the first and second blurring detecting sensors;
first and second direction determining sections for determining deflection directions of the first and second electric deflection members on the basis of first and second blurring amounts calculated by the blurring calculating sections;
first and second correction controlling sections for finding first and second voltage values supplied to the first and second electric deflection members in accordance with the deflection directions of the first and second electric deflection members output from the first and second direction determining sections;
first and second voltage generating sections for supplying voltages corresponding to the first and second voltage values found by the first and second correction controlling sections; and
a CPU for performing a blurring correction operation before the image taking operation by the image taking apparatus and inhibiting the blurring correction operation during the performing of an image taking operation by the image taking apparatus.
According to a fifth aspect of the present invention, there is provided an image taking apparatus comprising:
an operation means for outputting a designation signal for designating the performance of an image taking operation in accordance with a manual operation;
image taking means having an image taking optical system;
image taking control means for controlling the image taking means in accordance with a designating signal outputted from the operation means and performing an image taking operation;
detecting means for detecting a blurring state of the image taking apparatus;
blurring correction means arranged in the image taking optical system; and
blurring correction controlling means for controlling the blurring correction means in accordance with an output of the detecting means and thereby correcting an adverse effect resulting from the blurring of the image taking apparatus,
wherein the blurring correction controlling means operates the blurring correction means in a predetermined direction in accordance with the designating signal and the image taking controlling means performs the image taking operation after the blurring correcting means reaches a predetermined state.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.